A Phylogenetic Analysis of Greek Isolates ofAspergillusSpecies Based on Morphology and Nuclear and Mitochondrial Gene Sequences

Abstract

Aspergillus species originating from Greece were examined by morphological and molecular criteria to explore the diversity of this genus. The phylogenetic relationships of these species were determined using sequences from the ITS and IGS region of the nuclear rRNA gene complex, two nuclear genes (β-tubulin (benA) and RNA polymerase II second largest subunit (rpb2)) and two mitochondrial genes (small rRNA subunit (rns) and cytochrome oxidase subunit I (cox1)) and, where available, related sequences from databases. The morphological characters of the anamorphs and teleomorphs, and the single gene phylogenetic trees, differentiated and placed the species examined in the well-supported sections of Aenei, Aspergillus, Bispori, Candidi, Circumdati, Clavati, Cremei, Flavi, Flavipedes, Fumigati, Nidulantes, Nigri, Restricti, Terrei, Usti, and Zonati, with few uncertainties. The combined use of the three commonly employed nuclear genes (benA, rpb2, and ITS), the IGS region, and two less often used mitochondrial gene sequences (rns and cox1) as a single unit resolved several taxonomic ambiguities. A phylogenetic tree was inferred using Neighbour-Joining, Maximum Parsimony, and Bayesian methods. The strains examined formed seven well-supported clades within the genus Aspergillus. Altogether, the concatenated nuclear and mitochondrial sequences offer additional tools for an improved understanding of phylogenetic relationships within this genus.

Analysis of genetic and aflatoxin diversity among Aspergillus flavus isolates collected from sorghum seeds

“…Interestingly, we did not find clear separation between toxigenic and non-toxigenic A. flavus isolates when analyzing the ITS sequences as they were interspersed. Similar findings were reported by Baird et al [38] who stated that ITS markers failed to discriminate the toxigenic from the non-toxigenic isolates of A. flavus. Although phylogenetic relationships among A. flavus strains, isolated from different substrates and geographical regions, using the ITS domain has been reported by many researchers [39], better inferences of intra-species diversity will require exploration of multiple/different genomic loci.…”

Isolation of Aflatoxigenic Aspergillus flavus from Animal-Feed and Exploration of the Genetic Basis of Aflatoxin Biosynthesis

“…The evolutionary tree showed that isolate-1 closely relates to A. unguis, while isolate-2 and 3 are related to A. niger and A. flavus, respectively. Similar phylogenetic relationships based on ITS and IGS regions of the nuclear rRNA gene complex of fungus have been reported (Krimitzas et al, 2013). Significant efforts have also been reported by Chiba et al (2014) in which they developed phylogenetic tree analysis of aflatoxigenic and other non-aflatoxigenic species of Aspergillus group based on ITS sequences.…”

Aspergillus section Nidulantes (formerly Emericella): Polyphasic taxonomy, chemistry and biology

“…The morphology of the ascospores including colour, shape, size and ornamentation are of particular importance for species delineation and identification in Emericella (Thom and Raper, 1939, Christensen and Raper, 1978, Horie, 1980, Christensen and States, 1982, Ismail et al., 1995, Zalar et al., 2008, Matsuzawa et al., 2012, Guarro et al., 2012, Kritmitzas et al. 2013).…”